Patent GB-320375-A (GB)
Title: Improvements in the manufacture and production of anthraquinone and its derivatives
IPC: C07C46/00
Filed: 1928-07-06
Abstract: 320,375. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). July 6, 1928. Anthraquinone and its derivatives are obtained by treating the products obtainable by condensing one molecular proportion of an a-naphthoquinone, which may be substituted in the benzene nucleus, with one molecular proportion of a 1 : 3- butadiene, or the products obtainable by condensing one molecular proportion of benzoquinone with two molecular proportions of a 1 :3-butadiene in a molten state, or in neutral or alkaline diluting or suspending media, with agents capable of splitting off hydrogen by oxidation. Suitable diluting media are water, alcohols, hydrocarbons, heterocyclic compounds, and substitution products thereof, such as nitrobenzene, trichlorbenzene, naphthalene and its substitution products, and pyridine; aqueous caustic alkalies are particularly suitable. The process can often be accelerated by the employment of catalysts transferring oxygen, such as compounds of copper, cobalt, nickel and iron, particularly their oxides, vanadates and chromates. As agents splitting off hydrogen by oxidation, air, oxygen, hydrogen peroxide, potassium manganate, and perborates are specified; ozone is unsuitable, since it leads to the formation of ozonides, which split up, with the destruction of the anthracene ring system. If the reaction is carried out under milder conditions, preferably in the absence of oxidizing agents, for instance by heating the condensation products above their melting point, or in a highboiling indifferent medium, such as naphthalene, or if the condensation products are treated with acid media, such as aqueous or alcoholic hydrochloric or hydrobromic acids, or dilute sulphuric acid, intermediate products are obtained. The first stage in the production of such products is apparently a displacement of hydrogen; the condensation products from a-naphthoquinones and 1 : 3-butadiene yielding, for example 1 : 4-dihydro- 9 : 10-dihydroxyanthracenes. On dehydrogenation, these products yield bodies of a quinhydronic nature, which pass into hydrogenated anthraquinones and finally into anthraquinones. The 1 :4-dihydroanthraquinones and anthraquinones are also obtained by splitting out halogens or hydrogen halides from the condensation products from 1 : 3-butadienes and a-naphthoquinones which are substituted in the 2 or in the 2 and 3 positions by halogen. Such condensation products are obtainable by heating the components in a diluting medium, under pressure if necessary. The splitting out of halogens or hydrogen halides may be effected by heating the condensation products alone or in the presence of diluents, or by the action of acids, bases or salts. In examples (1) the condensation product from benzoquinone and 1 : 3-butadiene (2 mols.), obtained by heating the initial materials in an autoclave, is (a) boiled with aqueous or alcoholic caustic potash in the presence of air, or of other substances taking up hydrogen, such as potassium ferricyanide or sodium m-nitrobenzenesulphonate; the product is anthraquinone, (b) heated with alcohol and concentrated hydrochloric acid, and the isomeric. product thus obtained is heated with alcoholic ferric chloride, with the formation 1 : 4 : 5 : 8-tetrahydro-9 : 10-dihydroxyanthracene; the latter compound, on exposure to air, becomes violet, probably due to the formation of a body of quinhydronic nature, and on further treatment with ferric chloride yields 1 : 4: 5 : 8- tetrahydroanthraquinone, (c) converted into the intermediate isomeric product as in the preceding example and boiled with potash and ethyl or isopropyl, alcohol, or with metallic sodium and ethyl alcohol, yielding hexahydro-9 : 10-dihydroxyanthracene, which on heating with ferric chloride is converted into the corresponding hexahydroanthraquinone, and (d) heated in aqueous caustic soda in a stream of nitrogen containing a little oxygen; the product is mainly 1: 4: 5 : 8-tetrahydro-9 : :10-dihydroxyanthracene. (2) The condensation product from benzoquinone and isoprene (2 mols.) is boiled with aqueous caustic potash in the presence of air, or of another oxidizing agent such as potassium ferricyanide or sodium m-nitrobenzenesulphonate, the product is separated into 2 : 6-and 2 : 7-dimethylanthraquinones by extraction with methyl alcohol, in which the 2 : 7-isomer is readily soluble; the condensation product may itself be separated into two isomeric substances by fractional crystallization, and the 2 : 6- and 2 :7-dimethylanthraquinones obtained directly from the latter. (3) The condensation product from a-naphthoquinone and 1 : 3- butadiene is (a) boiled with caustic potash solution in the presence of' air or other oxidizing agents to give anthraquinone, (b) converted into the isomeric product by treating with hydrochloric acid or pyridine in the absence of air, or with aqueous potash in a current of nitrogen, or by heating alone or boiling with water or naphthalene in a current of nitrogen; the intermediate product, on dehydrogenation, for example by heating with alcoholic ferric chloride, gives first a blue product, apparently a quinhydrone, then 1 : 4- dihydroanthraquinone, and finally anthraquinone, and (c) boiled with aqueous or alcoholic ferric chloride to yield 1 : 4-dihydroanthraquinone. (4) The condensation product from alpha-naphthoquinone and isoprene, obtained by heating the components in ethyl alcohol, is boiled with aqueous caustic potash and air or other oxidizing agents; 2- methylanthraquinone is obtained. (5) The condensation product from a-naphthoquinone and 2 : 3-dimethyl-1 : 3-butadiene, obtained by heating the components in ethyl alcohol, is (a) heated with aqueous potash and potassium ferricyanide; 2 : 3-dimethylanthraquinone is obtained, and (b) heated with hydrochloric acid and alcohol to form the isomeric 2 : 3-dimethyl-1 : 4- dihydro-9 : 10-dihydroxyanthracene, which is partially dehydrogenated, yielding 2: 3-dimethyl- 1 : 4-dihydroanthraquinone, by treating with alcoholic ferric chloride. (6) The condensation product obtained by heating 5-amino-1 : 4-naphthoquirone with 2: 3-dimethyl-1 : 3-butadiene in alcohol, is boiled with caustic potash in a current of air; 6 : : 7 - dimethyl- I - aminoanthraqui none is obtained. (7) The condensation product obtained by heating naphthazarin with 1 : 3-butadiene in benzene is treated with caustic soda solution at ordinary temperature, while admitting air, 5 : 8- dihydro-1 : 4-dihydroxyanthraquinone is obtained; by heating with acetic anhydride it yields a diacetate, which is converted into quinizarin diacetate on treating with chromic acid in glacial acetic acid. The condensation product from naphthazarin and 2 : 3-dimethyl-1 : 3-butadiene, when similarly treated, yields 5 : 8- dihydro - 6: 7 - dimethyl - 1 : 4-dihydroxyanthraquinone; the diacetate obtained from this yields 6 : 7-dimethylquinizarin diacetate when treated with chromium trioxide in glacial acetic acid; by saponification, 6:7-dimethyl quinizarin is obtained. (9) The condensation product from 2- chlor-1 : 4-naphthoquinone and 2 : 3-dimethyl-1 : 3- butadiene is (a) boiled with caustic soda solution with the addition of a little sodium hydrosulphite; a solution of 2:3-dimethyl-1:4-dihydro-9:10- dihydroxyanthracene is obtained, which is converted into 2 : 3-dimethyl-1 : 4-dihydroanthraquinone by passing air though it, (b) heated with alcohol in a closed vessed to form 2 : 3-dimethylanthraquinone, and (c) boiled with pyridine while excluding air; on cooling, 2 : 3-dimethylanthraquinone separates out, while 2 : 3-dimethyl-1 : 4- dihydro-9 : 10-dihydroanthracene may be obtained from the mother liquid. (14) The condensation product from 2 : 3-dichlor-1 : 4-naphthoquinone and 2: 3-dimethyl-1 : 3-butadiene is boiled with alcoholic potash, 2 : 3-dimethylanthraquinone is obtained. (11) 2-Chlor-1 : 4-naphthoquinone is heated for several hours with 1: 3 butadiene; the product is 1: 4- dihydroanthranquinone. (12) 2-Chlor-1 : 4-naphthoquinone and isoprene are heated under pressure; the product is 2-methylanthraquinone. (13) The condensation product from 5 - nitro-2 : 3-dichlor-1 : 4-naphthoquinone (obtained by nitrating 5-nitro-2: 3-dichlor-1 : 4- naphthoquinone with a mixture of sulphuric and nitric acids) and 2 : 3-dimethyl-1 : 3-butadiene is heated with aqueous caustic potash and the product vatted with hydrosulphite and blown with air; 6 : 7-dimethyl-1-aminoanthraquinone is obtained. (14) The condensation product from 5-. nitro-2: 3-dichlor-1 : 4-naphthoquinone and 1: 3- butadiene is similarly treated; 1-aminoanthraquinone is obtained.